There is a link between a diet high in polyunsaturated fats and the risk of developing asthma, according to research published today. Children of three to five whose diet includes regular use of margarine spreads and foods fried in certain vegetable oils have double the risk of asthma.
Dr Michelle Haby and colleagues from the Royal Children's Hospital in Melbourne suggest that high polyunsaturated fat consumption increases the level of omega 6 fatty acids, which promotes the production of chemicals involved in lung inflammation. An inflammatory response is a key part of an asthma attack in which the airways in the lungs narrow, leading to shortness of breath.
The research, published in the medical journal Thorax, examined the diet of 1,000 Australian children and checked their response to dust mite, cow's milk and egg along with other common allergens. Pre-school children between the ages of three and five were included in the study.
The researchers chose two cities in Australia, one with a humid climate close to the coast and the other with a dry inland climate, to reflect different types of allergen, a known trigger factor for asthma.
A child with a positive allergic response to one or more of these allergens was 2 1/2 times more likely to have asthma than a child with a negative test. In addition, having a parent with a history of asthma doubled the child's risk of having the disease. However, a diet high in polyunsaturated fats more than doubled their risk of asthma.
Breast-feeding during the first weeks of life protects against asthma, according to the research, as does coming from a family with three or more older siblings.
The authors suggest that breast-feeding and dietary polyunsaturated fat are modifiable risk factors which, if changed, would make a substantial difference to the rising number of asthma cases. Up to 15 per cent of children in the Republic have asthma, reflecting a significant increase in the condition in the past 10 years.